What Does an Abnormal Pap Smear Test Result Mean?

Cervical cancer early detection uses the Pap smear screening test. Being told your result is abnormal may make you panic or feel frightened. This is entirely natural. What does an “abnormal” smear result mean, and what should you do?

Understanding an Abnormal Smear Result

An abnormal smear means that abnormal cells are seen when cells collected from the cervix are examined under a microscope in the laboratory. There may be many causes, ranging from a mild infection to cancer. Further cervical assessment, colposcopy and biopsy may be requested; depending on the result, repeat smear testing may be needed sooner than 3 years.

Note: Colposcopy allows close examination of the cervix, vagina or vulva using an illuminated instrument called a colposcope. It magnifies the cervix, allowing better examination and visualization.

Abnormal smear results are actually quite common. In the United States alone, approximately 3 million women receive abnormal results each year. About 12.000 of these, or one in 250, will progress to cervical cancer.

Cellular Abnormalities and Cancer Development

The most common cellular abnormality in the cervix is dysplasia. In dysplasia, cells stop looking similar to one another and undergo structural changes. When dysplastic changes are marked and involve the full thickness of an organ’s lining, they are called carcinoma in situ , a precancerous stage. Dysplasia is reversible.

Dysplastic cells are classified as follows:

• Atypical squamous cells of undetermined significance – (ASCUS, atypical squamous cells of undetermined significance)
• Low-grade squamous intraepithelial lesion – (LGSIL, low grade squamous intraepithelial lesion)
• High-grade squamous intraepithelial lesion – (HGSIL, high grade squamous intraepithelial lesion)
• Atypical glandular cells on a Pap smear – (AGC, atypical glandular cells on a Pap smear) Most dysplastic cells do not change or cause a problem.

Some that change become precancerous , meaning cancer precursors; these lesions may progress to cancer.

When some of these cells later involve the full thickness of the cervical lining, the condition is called carcinoma in situ , a precancerous stage, but it has not penetrated beyond the basement membrane, the lowest layer of the lining. It is called cervical cancer only when it crosses beyond the basement membrane.

ASCUS – atypical squamous cells of undetermined significance

This is the most common abnormal smear result (75 percent). Normally, the cervical lining contains 2 cell types. Squamous cells occur on the ectocervix, the surface facing the vagina, while secretory columnar epithelial (glandular) cells are found in the endocervical canal. In ASCUS, squamous cells are found where they normally should not be, in the endocervical canal. The cause is vaginal infection or human papillomavirus (HPV) infection, generally sexually transmitted.

SIL – squamous intraepithelial lesion

This indicates abnormal changes in squamous cells that have developed into a lesion. It is not a cancer diagnosis, only abnormalities assessed by size, shape and physical characteristics:

• Low-grade squamous intraepithelial lesion (LGSIL) consists of mild abnormalities, usually due to an HPV infection. Most such infections resolve without treatment.
• High-grade squamous intraepithelial lesion involves changes that may be associated with the development of precancerous cells.

AGC – atypical glandular cells

Glandular cells are another cell type lining both the uterus and cervical canal. An AGC smear result means changes have occurred in cells in this area, raising suspicion of a precancerous lesion or cancer.

What Happens If You Have an Abnormal Smear Result?

If you receive an abnormal smear result, your doctor may request additional tests. This will largely depend on the laboratory classification, your current health and your doctor’s experience.

Possible approaches include:

• Careful monitoring with regular smear screening
• HPV testing (including reflex HPV testing using cells from the Pap smear)
• Biopsy of any abnormal tissue through colposcopy.
• Endocervical sampling (scraping the cervical canal with a spoon-shaped instrument)
• Uterine sampling (taking tissue from the uterus if abnormal cells are suspected to originate there)
• Excisional treatment (cone biopsy) to remove the lesion or growth. Cold conization or cone biopsy removes a cone-shaped piece from the center of the cervix. If performed with a scalpel, it is called cold conization; with a laser, laser conization; and with an electrically powered loop instrument, LEEP (LLETZ, loop electrosurgical excision procedure).

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